The present invention relates in general to minimizing electrical power consumption of pooled computer resources, and, more specifically, to turning pooled resources on and off in an efficient manner that maintains quality of service (QoS) from a service delivery network.
Service delivery networks for providing telecommunication and/or data processing services such as web pages or electronic multimedia typically use pooled computer resources in a co-located facility or data center. Computing grids employ a large number of pooled computer resources that may be allocated on request to users within a group. A primary difficulty faced by service providers utilizing pooled computing resources relates to electrical power consumption and heat production. As computer processors have become increasingly powerful, they have also become increasingly power hungry and hot. In response, microprocessor chip manufacturers have taken steps to limit the power consumption and heat production using processor power management schemes such as variable clock rates and by developing multi-core processor chips. Some manufacturers are working on shutting down portions of a processor when they are not needed so that power consumption and heat production can be reduced.
While processor chip improvements are helpful, a great deal of electrical power continues to be wasted in many applications. Demands for capacity from a particular service can vary significantly during a day (e.g., up to 500% variations). Resources that are not utilized or are underutilized waste power and create unnecessary heat by operating the associated microprocessors and also the support components and peripherals associated with the microprocessor or computer.
Computing resources such as standalone computers and servers or individual processing blades in blade servers or clusters are known which are capable of being remotely stopped (i.e., powered down) and restarted. Attempts have been made to match active resource levels of pooled resources to the actual demand for services by activating only those resources necessary to meet the current demand. Such systems suffer a serious drawback, however, in that the restart time after a computer or blade has been shut down is sufficiently long that computer processing performance of the system lags behind the increase in demand.
Quality of Service (QoS) relates to the obligation of a service provider to maintain performance levels in accordance with certain guaranteed criteria. For example, transmission rates and/or error rates at a guaranteed level may be needed for purposes of transmitting video and/or multimedia data. Under fluctuating load conditions, when increased resources become necessary QoS levels may be adversely affected by the inherent time delays associated with restarting halted resources. The lead-time for adding additional capacity from halted resources in a pool includes time for starting associated hardware, loading an operating system, and loading the appropriate applications run by the resource. Thus, prior art attempts to reduce electrical power consumption have not been appropriate in the context of a service provider that needs to guarantee a particular QoS.